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Crank Pos Sensor / reference volts???

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Old 03-06-2024, 08:56 AM
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Originally Posted by Sworvoo
Did you check your oxygen sensor(s). I had somewhat similar issues and it was a bad upstream sensor.

Any vacuum leaks? I had a few leaks too and found them with a cigar.
there are only a couple of vacuum lines... I just installed a new MAP sensor and the rubber (L shaped) line which is very short looked ok. the other line looks ok but I will double check it. (I dont smoke, so no cigars/cigs)

Are there other vacuum lines I am missing???
Old 03-06-2024, 09:30 AM
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You can get a vacuum gauge on Amazon pretty cheep or borrow one from a parts store to see if you actually have one. I had a few small leaks that meat have all contributed to the issue but I fixed too many things at the same time to isolate the issue. One of the leaks was from the throttle body where the shaft rotates. I guess when I cleaned it I cleaned all the grease out too.
Old 03-08-2024, 10:30 AM
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ok... finally got some testing done with the oscilloscope:

Both of these sensors are getting proper 5.13v power supply, verified with the multimeter. Grounds are good.

I am getting no square waves from the Cam Pos Sensor.

I am getting square waves from the Crank Pos Sensor but they are not consistent. it puts out 4 sq waves and then skips and then another 4, and this repeats...

Please advise .....

Andy
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Old 03-08-2024, 10:56 AM
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Whoa, aren't we Mr. Techno now!

That's how the crank position sensor is supposed to look:


Old 03-08-2024, 11:00 AM
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The cam coil sync sensor thing should have sent a signal as above. Check to make sure it's not a wire, but sounds like it's dead.
Old 03-08-2024, 11:05 AM
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BTW crank signal groups have to be completely contained within cam signals (whether it's -0- or 5 VDC) or "synced".

Can cover later if necessary.
Old 03-08-2024, 11:15 AM
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Originally Posted by Dave51
The cam coil sync sensor thing should have sent a signal as above. Check to make sure it's not a wire, but sounds like it's dead.
getting nothing from the Cam Pos Sensor... it's a flatline. ground wire checks out fine, and the power is at 5.13v coming into the sensor.
Old 03-08-2024, 12:28 PM
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That was with the engine running.
Old 03-08-2024, 03:07 PM
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Sound to me you have done enough to justify a new sensor.
Old 03-08-2024, 05:55 PM
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Originally Posted by Dave51
BTW crank signal groups have to be completely contained within cam signals (whether it's -0- or 5 VDC) or "synced".

Can cover later if necessary.
Not sure what you mean here... but seems to me like the cam pos sensor is dead. Getting a new one (genuine Mopar).
Old 03-09-2024, 03:26 AM
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Superimpose CPS on CKS. Each group of 4 CKS signals has to be completely contained within a CPS phase (either -0- or 5 VDC). You cannot have like 3 CPS in a -0- VDC phase and one outside in a 5 VDC phase.

Good:



Bad:


Last edited by Dave51; 03-09-2024 at 03:30 AM.
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Old 03-09-2024, 09:23 AM
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Thanks for the visual... makes sense. I ordered a genuine Mopar cam sensor... should be here in a few days. Hoping that is the problem.
Old 03-09-2024, 10:38 AM
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It's undoubtedly "a" problem. Whether it's the "only" problem remains to be seen.
Old 03-10-2024, 10:25 PM
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Originally Posted by Dave51
It's undoubtedly "a" problem. Whether it's the "only" problem remains to be seen.
I found intermittent Cam Sensor signals on my 98. Turned out to be worn distributor shaft bushings. Replaced the distributor.
Old 03-14-2024, 05:57 AM
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Originally Posted by Sworvoo
Did you check your oxygen sensor(s). I had somewhat similar issues and it was a bad upstream sensor.

Any vacuum leaks? I had a few leaks too and found them with a cigar.
There are no codes for a bad O2 Sensor. How would you know if it's gone bad?

I am not seeing any vacuum leaks around the intake manifold. What about this fuel regulator? does it have vacuum hoses?


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